Process for heating and purifying or softening water.



APPLICATION FILED MAR. 20, 1911.

Patented June 9, 1914 IVf/OCJ'S e s k Kim ST'ATES PATENT OFFICE.

CHARLES ERITH, OF LONDON, ENGLAND- PROCESS FOR HEATING AND PURIFYING RSOFTENING WATER 1,099,433. p ifi of Letters Patent PatentedJune 9, 1914.Application filed March 20, 1911. Serial No. 615,476.

To all whom it ma concern: as a considerable proportion of the impuri-Be it known t at I, CHARLES Earrrr, a ties are deposited on theeconomizer tubes subject of the Kingof Great. Britain, residas scale andconsequently haveto be removed ing at 70 Gracechurch street, .in thecity and periodically by boring or other similar opcounty of London,England, have invented erations. 60 a certain new and useful Process forHeat According to this invention the aforesaid ing and Purifying orSoftening ater, of objection is avoided by purifyin and sofwhich thefollowing is a specification. toning the water in a vessel vente to theat- This invention relates to the heating and mosphere and the steamheating required is purifying or softenin of water for indusmlnlmizcd byheating the water prior to its 65 trial purposes, such or instance assteam admission thereto, by waste gases from boilplants for which hot.soft water is required ers or furnaces, to a temperature only and forother purposes; the object-beingto Slightly below that needed for thedesired effect the desired treatment in the most ecomechanical andchemical purification f the nomical manner by utilizing the heat ofWater. The additional heat required to 70 waste gases. bring the waterto the required temperature The invention is particularly applicable m11, nd is c nsequently supplied by a for employment with apparatus ofthecharmlnlmum quantity of exhaust or waste acter described in thespecification of Brite flm- The preliminary and final heating 2o ishLetters Patent granted to me No. 6,946 18 obtained by means of aneconomizer 75 of 1904, in which a combined chemical and which maycomprise a series of rows of mechanical purificationis obtainedby-heatpipes, placed inthe path of the waste gases ing the ater withsteam to about 210 Fahr, from the lJOilBI'S OI furnaces, andwhich iswhile subjecting the same to the actio of usually built in two or moresections through a single re-agent, usually carbonate of soda, which theWater is passed. 80 i a ve sel vented t the atmos h Al- In order thatthe invention may be clearly th h h t or waste steam i suitablunderstood and readily carried into effect, for this purpose it oftenhappens that sufii- I will proceed to describe the same with refcientexhaust steam is not available for the erence to the accompanyingdrawing in complete heating of the feed water, so that which I haveillustrated diagrammatically s5 partof the heating has to be eflect d byliv the appllcation of the invention to asteam steam because in theeven-t of the water being generating plant. not sufiiciently heated toeffect the above- The tank A contains a supply of the feed mentionedmechanical and chemical purifiwater to be treated.

cation with a single re-agent, such as carbon- B isan economizer placedin the main 90 ate of soda, it would become necessary to flue B; O is aheating and softening appause a further re-agent such as lime, to obtainratus of the character described 'in my the desired purification andsoftening of the aforesaid prior patent, and D D represent a feed Water.battery of boilers. The .economizer B usu- 40 In order to overcome theaforesaid objccally comprises two or more groups or section, anexpedient, previously proposed in tions of pipes, of which, thegroupnearest connection with the softening and purifyto the end of theeconomizer at which the ing of feed water, is adopted the water beingwaste gases enter, receives the most heat, the heated in an economlzerduring, treattemperature of the gases falling as they ment. In theseearlier methods of treatment, on'their way to the chimney flue Bhowever, the necessary re-agent or chemical Each successive row of pipesreceives less precipitant is mixed with the feed water and heat and "thewater is heated to a correspondthe mixture heated in the economizer soing degree in each row. When hard water that the softening takes placein the latter is pumped through the economizer the preunder ressure. Themixture is then passed cipitation of scale and sludge forming solthronga separator and so on alternately ids occurs in the rows of pipes whichreceive. through a section or portion of the econthe most heat, and inorder to prevent the omizer and through a separator until the formationof scale it is necessary to soften water is sufliciently purified. Thismethod or purify the water passingthrough these 55 of treating the feedwater is objectionable rows. In the arrangement shown, two 119 groups ofpipes Z), 6' are provided in the the gases which traverse this group ofpipes without the formation of scale. The water before being passedthrough the group of pipes b is, however, purified in the apparatus Cand although its temperature is sufficient for the formation of soale,nonewill be formed as the impurities in the water have been removed,owing to itstreatment in the heating and softening apparatus 0.

In the normal working of the plant the' hard water passes from the tankA, through the pipe at to the part b of the economizer through the pipesof which it circulates and from thence it passes by way of the pipe a tothe steam heating and softening apparatus C. -From this apparatus thehot purified wateris pumped by the feed pump Fthrough the second groupofpipes b of. the economizer to the boilers D by way of the .7 pipe 6Suitable connections and valves are provided whereby the purifying andsoftening apparatus C and economizer B may be disconnected for cleaningwithoutshutting down the boilers D. Owing to the heating and softeningof the water which is effected between the passage of' the'water throughthe successive groups b, b of the economizer, scale formation iseffectively avoided. The flow of the water through respective sectionsof the economizer in the manner described enables a greater amount ofheat to recovered from thewaste gases th'an'would be the case ifsoftened waterat about 210 Fahr. was pumped directly from the purifyingapparatus through the entire economizer, as the transfer of heat isproportional to the difference in temperature between-the gases and theWater. Y

By preheating the hard or unpurified water by hot waste gases in theeconomizer, most of the steam otherwise required for the purifying andsoftening apparatus is saved. The hard water flowing through the groupof pipes b of the economizer enters the purifylng apparatus 6, at

a temperature of about 180 'Fahr. and isthere mixedwith a proportionatequantity of soda-solution, the waterbeing further heated by flowing overa series of trays ar-- ranged in-cascade in a steam bath suppliedfrom-the exhaust steamfrom the pump F by way of the pipe f, whereby thechemical and mechanical purification referred to in my aforesaid priorpatent is effected.

When the water entering the apparatus C has been heated'bythe wastegases to a temperature of about 180 F. as described, very little steamis required'to effect the heating of the water to a temperature of 210F. which is the temperature necessary I for obtaining the desiredpurification.

The exhaust steam from the feed pump F usually sufiices, but, ifnecessaryadditional exhaust or live steam can be employed. The flow ofwater through the group of economizer pipes b is controlled by a floator the like (not shown) in the apparatus C, and this float also servesto control the admission into the apparatus of the necessary re-agent,the float admitting water to correspond with the demand of the pump.

The final heating of the feed water is effectedin the group b of theeconomizer, by the waste gases inthe usual manner and the purified waterenters the boilers at a temperature of about 250 to 300 Fahr.- theeconomizer and boilers being kept free from scale by the efiicientapplication of the aforesaid process of purification. I v a Although Ihave referred to certain temperatures at the various stages of thetreatment it will be readily understood that these will be liable tovariation within certain limits for different uses of the invention.

What I claim and desire to secure by Letters Patent of the United Statesis 1. The method of heating and purifying feed water, which=consists inpreliminarily heating the water in an economizer by hot waste gasesfromthe boiler furnace to a temperature below "that at i which.substantial deposition .of impurities occurs, transferring the water toa suitable purifier and there adding an appropriate chemical reagent toeffect purification thereof, and finally re- 7 2. The method of amazingthe heat of" waste furnace gases in the heating and purification of feedwater, which consists in transferring the heat of the gases to the waterin an economizer until the temperature of the water approximates that atwhich the contained impurities would be deposited, removin the waterfrom the economizer and e ecting the deposition of the impurities, andfinally returningthe purified water to the economizer and raising; it tothe feed temperature by the heat of the waste ases; substantially asdescribed.

3. T e method of utilizing the heat of waste furnace gasesin the heatingand purification. of feed water, which consists in transferring the heatof the gases to the water in an economizer until the temperature of thewater approximates that at which the contained impurities would bedeposited, removing the water from the economizer and effecting thedeposition of the impurities with the aid of steam heat transferredthereto, and finally returning the purified water to the economizer andraising it to" the feed temperature by the heat of the waste gases;substantially as described. I

4. The method of heating and purifying feed water with the aid of wastefurnace gases, which consists in transferring the heat of the gases tothe-water in an economizer until the temperature of the waterapproximates that suitable for chemical purification by a singlereagent, transferrin the water to a suitable purifier, there adding tothe water an appropriate reagent and steam heat to remove thescale-formm impurities, and finally returning the puri ed water to theeconomizer and there bringing it to the feed temperature by the heat ofthe waste furnace gases; substantially as described.

5. The method of operating an economizer heated by waste furnace gasesin the heating and purification of feed water, which consists 1n passingthe water through the economizer at temperatures below that at whichdeposition of contained impurities takes place, removing the water fromthe economizer and passing it throu h the temperature of deposition bythe a dition of steam heat; substantially as described.

6. The method of operating an economizer heated by waste furnace ases inthe heating and purification of eed water, which consists in passing thewater through the economizer at temperatures below that at whichdeposition of contained impurities takes place, removing the water fromthe economizenpassing it through the temperature of deposition by theaddition of steam heat, and finally returnin the purified water to theeconomizer and t ere heating it to the feed temperature; substantiallyas described.

In testimony whereof I afiix my signature in presence of two witnesses.

CHARLES ERITH.

Witnesses:

W. J. SIKER'I'EN, Gno. M. FRANKLIN.

